Butterfly valve disc



FIG. 1 is a perspective view of a butterfly valve disc showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is a cross-sectional view taken along lines 8-8 in FIG. 2.

The dashed-dot broken lines shown in the figures are included for the purpose of illustrating bounds of the claim and form no part of the claimed design. 

CLAIM The ornamental design for a butterfly valve disc, as shown and described. 